62 A CHEMICAL SIGN OF LIFE 
in the narcotic solution, care being taken that the claw 
muscle did not come in contact with the solution. After 
ten minutes it was removed, freed from excess liquid by 
means of filter paper, its state of excitability determined 
by stimulation, and, with claw attached, it was placed 
in a moist chamber for ten minutes, which is the time 
TABLE VII* 
EFFECTS OF ETHYL URETHANE ON CLAW NERVE OF SPIDER Crap, Libinia canaliculata 
TREATED BY 
EFFEects On| AFTER mn. Amount oF CO; Pro- 
Concen- For Excita- RETURN TO i vo. DUCED BY 10 MG. OF 
tration in| How BILITY SEA-WATER MINUTES NERVE IN 10 MINUTES 
Sea-Water | Long 
. 1, Excitable No change | 7.9X10~7 g. at 2092 
oper cent. .}I0 min. nerve : 
2, Inexcit- | Excitable No change | 5.7 X10 7 g.at 22° 
able nerve 
1 per cent..{10 min.| Excitable Excitable No change |21.7 X10 7 g. at 23°8 
2 per cent../10 min.| Narcosis Excitable No change | Not determined 
very slow : : 
3 percent..|10 min.| Slow, partial) Excitable No change | Not determined 
narcosis 
4 percent..|10 min.| Practically | Good return} No change |3.3X10~7 g.at21°-21°5 
narcotized 
5 percent..|10 min.| Completely | Recovery is | No change | Not determined 
narcotized| not always 
good 
* Since our previous determinations of the carbon dioxide production of the spider 
crab’s nerve were made at a much lower temperature (15° to 16°C.), the work was 
repeated at the higher temperature at which most of the present experiments were made. 
In order to make the comparison a rigid one, the normal nerve was subjected to a treat- 
ment similar to that employed with the narcotized nerve, except that it was not narcotized. 
It was isolated, quickly weighed, and immersed in sea-water for ten minutes, after which 
the rate of carbon dioxide production was determined in the usual way. As was expected, 
the nerve exhibited a somewhat higher rate of metabolism at the higher temperature. 
The results are incorporated in the table. 
usually required in making a determination of the 
carbon dioxide production. After this the nerve was 
brought back to fresh sea-water and the return of irrita- 
bility was determined, as evidenced by contraction of the 
claw or joint in response to the electrical stimulation 
of the nerve. Thus the essential conditions obtaining 
